merge: don't call copies.mergecopies unless we need to
This reduces the amount of time we spend calculating when doing a clean
non-merge update. In a large repo, the time dropped from 10.1 seconds
to 3.4.
--- a/mercurial/merge.py Sat Feb 09 21:24:24 2013 +0000
+++ b/mercurial/merge.py Sat Feb 09 21:24:36 2013 +0000
@@ -200,6 +200,8 @@
pa = wctx
elif pa == p2: # backwards
pa = wctx.p1()
+ elif not branchmerge and not wctx.dirty(missing=True):
+ pass
elif pa and repo.ui.configbool("merge", "followcopies", True):
ret = copies.mergecopies(repo, wctx, p2, pa)
copy, movewithdir, diverge, renamedelete = ret
--- a/tests/test-subrepo.t Sat Feb 09 21:24:24 2013 +0000
+++ b/tests/test-subrepo.t Sat Feb 09 21:24:36 2013 +0000
@@ -210,7 +210,6 @@
subrepo merge f0d2028bf86d+ 1831e14459c4 1f14a2e2d3ec
subrepo t: other changed, get t:6747d179aa9a688023c4b0cad32e4c92bb7f34ad:hg
getting subrepo t
- searching for copies back to rev 1
resolving manifests
branchmerge: False, force: False, partial: False
ancestor: 60ca1237c194, local: 60ca1237c194+, remote: 6747d179aa9a